Apparatus for handling workpieces

ABSTRACT

A process for handling workpieces by sequentially loading them into holder portions of continuously moving carrier assemblies, simultaneously abruptly shifting a group of such holders to workpiece-release positions at a discharge station while continuing movement of the carrier assemblies back toward the loading stations, and resetting the holders prior to arrival at the loading station in order to receive additional workpieces. The apparatus includes a holder trip mechanism portion of each carrier assembly, means supporting such assemblies for sequential movement along an endless path, an actuating assembly for simultaneously triggering the trip mechanisms of a group of the carrier assemblies at the discharge station and reset means for returning the holders to workpiece-engaging positions. The process and apparatus is especially adapted for use in combination with a system for temperature-conditioning elongated molded parts.

This is a division of application Ser. No. 480,604, filed June 19, 1974which in turn is a division of application Ser. No. 424,866, filed Dec.14, 1973, now U.S. Pat. No. 3,880,301.

BACKGROUND OF THE INVENTION

This invention relates to method and apparatus for handling workpiecesand more particularly to collecting, conveying and releasing moldedparts to a temperature-conditioning chamber.

In copending application Ser. No. 418,075, filed Nov. 21, 1973, assignedto the present assignee, there is disclosed a high speed, high volumesystem for temperature-conditioning workpieces such as elongated,thermoplastic, molded parts in order to bring them to molecularorientation temperature prior to reshaping into articles such ascontainers. In such disclosed system, a plurality of parts are supportedin parallel in bar assemblies sequentially presented to a loadingstation and then passed through a chamber containing a suitable heattransfer means. The system has numerous advantages as therein disclosed,a major one being minimum contact of the parts with the components ofthe apparatus. The need is apparent for a system with a similar scope ofadvantages, broadly applicable to the handling of workpieces in general,and specifically to elongated, molded, thermoplastic parts upstream of atemperature-conditioning station such as that disclosed in thepreviously mentioned copending application.

SUMMARY OF THE INVENTION

Accordingly, it is a primary object of this invention to provide afacile method and apparatus for handling workpieces, particularlyelongated, thermoplastic molded parts which are to betemperature-conditioned in an immediately downstream station.

Another object of this invention is to provide such method and apparatuswhich is not reliant on substantial contact between hot deformable partsand the handling apparatus or on numerous workpiece position-orientingsteps.

A further object of this invention is to provide a continuous method ofreceiving workpieces from an upstream station, conveying them inindividual carriers to a discharge area where they are automaticallyejected into waiting receptables and then recycling the carriers withoutstopping to pick up additional workpieces.

A specific object of this invention is to provide an improved carrierassembly for handling parts between adjacent work stations.

Other objects will in part be obvious and will in part appearhereinafter.

These and other objects are accomplished by providing a workpiececarrier assembly comprising post means, a holder pivoted to the postmeans, a trip mechanism for abruptly shifting the holder to aworkpiece-release position, and means associated with the holder forcooperating with nearby position-changing meaans for returning theholder to its workpiece-engaging attitude.

A plurality of such assemblies are preferably provided in combinationwith means supporting the assemblies for continuous sequential movementthrough loading and discharge stations and with an actuating assemblyfor simultaneously triggering the trip mechanisms of a group of suchplurality of carrier assemblies at the discharge station.

The apparatus is especially adapted for use with equipment fortemperature-conditioning the workpieces or parts which includes ahorizontally extending heat transfer chamber, support means for carryinga plurality of parts in side-by-side relationship through the chamberand means for releasably detaining the support means at a feed end ofthe chamber while the parts are deposited in the support means on beingejected from the carrier assemblies under the influence of the actuatingassembly.

The process comprises sequentially loading workpieces into holders ofindividual carrier assemblies, continuously moving the loaded assembliesalong a path toward a discharge station, simultaneously abruptlyshifting a plurality of such holders at the discharge station to releasepositions to discharge the workpieces without stopping movement of thecarrier assemblies and then resetting the holders before ariving back atthe loading station to receive additional parts.

BRIEF DESCRIPTION OF THE DRAWINGS

In describing the overall invention, reference will be made to theaccompanying drawings wherein:

FIG. 1 is a plan view of apparatus embodying the present invention;

FIG. 2 is an elevational view of the apparatus of FIG. 1;

FIG. 3 is a sectional view in detail along 3--3 of FIG. 2;

FIG. 4 is a sectional view along 4--4 of FIG. 3;

FIG. 5 is a schematic, partially sectioned view in the direction of 5--5of FIG. 3; and

FIG. 6 is an elevational view of an alternative embodiment of thecarrier assembly portion of the invention.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Referring now to the drawings, there is shown in FIGS. 3 and 6 aworkpiece carrier assembly generally indicated as 10 comprising uprightpost means 12 which includes hollow post 14 telescopically received insleeve 16 and secured thereto by cotter pin 18. Post 14 may have aseries of vertically spaced, horizontally aligned holes 19 which may bepositioned adjacent similar holes in sleeve 16 for insertion of pin 18in order to adjustably position sleeve 16 and consequently the partscarried by it with respect to post 14. In this manner the extent of freefall of a workpiece during either feed to or discharge from (e.g., 21 inFIG. 2) the holder portion of a carrier assembly can be regulated.

Holder portion 20 (FIG. 4) is pivoted at 22 (FIG. 3) to post 14 andsleeve 16 and has means including roller 24 journaled for rotation viabearing 26 projecting outwardly therefrom for cooperating with nearbyposition-changing means (132 in FIG. 1) for returning holder 20 to theworkpiece-engaging attitude of FIG. 3. In FIGS. 1-4 the holder portionis in the form of U-shaped clip 20 opening outwardly at 30 with thedistance 28 (FIG. 4) between opposing legs of the clip being greaterthan diameter 29 of part 144 (FIG. 3) but less than that of enlargement200 thereof so that the latter rests on clip 20 when part 144 is carriedby assembly 10. In the embodiment of FIG. 6, holder portion 21 is asolid platform, which may be of resilient material, having depression 32in which a spherical end of the workpiece is seated. In the embodimentof FIG. 6, vertical cradle portion 70 secured to post 14 above platform21 surrounds the upper portion of part 144 and serves to prevent it fromtoppling off during movement of the carrier assembly.

Each assembly 10 further includes means such as a pressure actuated tripmechanism for abruptly shifting clip 20 (or platform 21) downwardly froma locked position toward and against lower end 34 of post 14 to therelease position shown at 35 in outline form in FIG. 6. Such tripmechanism comprises a pair of torsion springs 36 on either side of clip20 wedged between pins 38 and 40 on sleeve 16 and holder arm portions 39for biasing holder 20 downwardly toward post end 34. Latch meansgenerally indicated as 42 associated with holder arm portions 39 andpost means 12 secure holder 20 in the workpiece-engaging position ofFIG. 3 and includes latch 44 secured at its inner end at 45 on eitherside to extensions 46 which in turn are pivoted to post means 12 via pin48 extending through both sleeve 16 and hollow post 14 above holder 20.Slot or cutout 50 at the opposite free end of latch 44 receives endportions 52 of holder arm portions 39 which, via abutment against ledge54, resist downward urging of springs 36 to thereby fix clip 20 in ahorizontal, locked, operative position perpendicular to the verticalaxis of post 14. Compression spring 58 beneath pivot connection 48 urgeslatch 44 outwardly away from post 14. Set screw 60 threadably secured inlatch 44 projects toward post 14 above pivot 48 and adjustably limitsthe extent of outward bias of latch 44 by spring 58 away from post 14via abutment with the latter. By advancing screw 60 toward or away frompost 14 the position of free end 62 of latch 44 may be set with respectto horizontal bar 64. In lieu of cradle 70 (FIG. 6) funnel member 66 canbe used to guide a workpiece into holder 20 and may be mounted aboveholder 20 and secured to adjustably positioned sleeve 16 also via cotterpin 18. The narrow outlet end of funnel 66 is aligned above the openingof clip or holder portion 20.

A plurality of adjacent carrier assemblies 10 are provided asschematically indicated in FIGS. 1 and 2 and preferably occupy the fullperiphery of the apparatus, i.e., along the three sides of thetriangular layout of FIG. 1, though not so indicated therein forpurposes of simplicity.

Means supporting each carrier assembly 10 for continuous, sequentialmovement through a loading station generally indicated at 72 in FIG. 2and a discharge station generally indicated at 74 in FIG. 1, includesvertically spaced upper 76 and lower 78 (FIG. 3) chains mounted formovement along an endless path via a suitable means such as aconventional motor, not shown, attached to shaft 80 (FIG. 3). Coaxialsprockets 82 and 84 (FIG. 2) are conventionally secured tobearing-mounted rotatable shaft 86 between loading and dischargestations 72 and 74 with similar sprockets 81 and 83 provided at loadingstation 74 and intermediate area 88 (FIG. 1). Upper 90 and lower 92guide bars (FIG. 3) adjacent chains 76 and 78 extend along the entirelengths thereof. Upper and lower clips 94 and 96 (FIG. 3) slidablystraddle bars 90 and 92 and are secured via screws to the upper andlower ends of a post 14 of a carrier assembly and to chains 90 and 92 atequally spaced intervals, and serve to stabilize each carrier assembly10 in the horizontal 98 (FIG. 3) and vertical 100 directions duringmovement with such chains.

Latch deflecting projecting means, such as vertically adjustable disc102 on shaft 86 (FIG. 2) having an outer edge lying in the path of thelatch 44 of each carrier assembly, may be provided to trigger each tripmechanism when a holder 20 is supporting a workpiece as it passes disc102.

Actuating or trigger mechanism 104 (FIG. 1) at discharge station 74 isprovided for simultaneously triggering the trip mechanisms of a group,such as the ten shown at 106 in FIG. 2, of the plurality of carrierassemblies 10. Assembly 104, comprises horizontal bar 64 having a lengthat least equal to the portion of the path occupied by the holderportions of the series of adjacent assemblies to be simultaneouslyactuated during a cycle of the apparatus. In the illustrated embodiment,such length is substantially equivalent to distance 106 in FIG. 1.Trigger assembly 104 includes means for cyclically pivoting bar 64 intoand out of contact with end portions 62 of the latch members (FIG. 3) toactuate the trip mechanisms thereof to abruptly shift holders 20 totheir workpiece-release positions. Such means in the illustratedembodiment comprise (FIG. 2) first 108 and second 110 link membershorizontally spaced from each other and pivoted at 112 and 114respectively to bar 64 and at 116 and 118 to rigid support plate 120mounted on a suitable frame 122. Intermediate link 124 is similarlypivotably secured at both its ends to bar 64 and support 120respectively. Tension spring 126 secured to link 124 and anchored tosupport plate 120 urges bar 64 toward the at-rest position of FIG. 1,i.e., away from the alternative, operative bar-engaging position inwhich link 124 is parallel with plane 128. Normally open solenoid valve130 pivotally secured to link member 108 urges bar 64 via thejust-described link connections toward such alternative operativeposition when energized.

Trip mechanism reset means for returning each holder portion 20 to theposition of FIG. 3 are provided between discharge and loading stations72 and 74 and includes lifting structure such as cam 132 having upwardlyinclined edge 134 automatically engageable by roller 24 of each holderportion 20 as its carrier assembly moves through this area during itspath of travel. Edge 134 cooperating with roller 24 thus mechanicallyurges each holder 20 upwardly against the bias of springs 36 untilholder arm portions 39 snap into cutout 50 of latch 44 against ledge 54.

Though broadly operable in any environment, the system just described isparticularly adapted for use with temperature-conditioning equipmentwhich may, for example, comprise a horizontally extending heat transferchamber schematically illustrated at 136 in FIG. 1 having vertical sides138 and 140, FIG. 2. As described in copending application Ser. No.418,075, filed Nov. 21, 1973, receiving or support means 142 (FIGS. 2, 3and 5) may be provided for carrying a plurality of molded parts, such aspreforms 144, in side-by-side parallel relationship through chamber 136.Support means 142 includes a suitable housing 143 containing a pluralityof sockets 146 linearly arranged across the width of chamber 136 beneaththe holder portions 20 of a group of carrier assemblies 10 in dischargestation 74 in the manner most clearly shown in FIG. 3. The centerlinedistance between immediately adjacent sockets is preferably equal tothat between immediately adjacent holders 20.

As illustrated in FIG. 5, means are provided as part of thetemperature-conditioning equipment to releasably detain each supportmeans 142 at the feed end of conditioner 136, which in the illustratedembodiment is considered to be carrier assembly discharge station 74whereat preforms 144 are deposited in sockets 146. Such releasabledetaining means includes, as further described in said copendingapplication, protruding boss 148 at the end of support means housing143, seated in an open ended slot 150 of escapement wheel 152 which isintegral with sprocket 154, the latter meshing with chain 156 which inturn is driven by power generated from a suitable conventionalcyclically electrically energized intermitter (not shown) forintermittently turning each wheel 152 a predetermined angular amount. Asimilar set of parts as just described, though not shown, is located atthe opposite end of support means 142 on the right side in FIG. 5. Thus,receiving or support means 142 when such intermitter is in deenergizedcondition temporarily dwells in station 74 while preforms 144 aredeposited in sockets 146, whereupon the intermitter is energized torotate wheels 152 to release bosses 148 from confinement in slots 150and thus allow support means 142 to advance through chamber 136 via asuitable conveying means, not shown, such as coacting chain and sprocketmembers.

Adjustable chute assembly 158 (FIG. 5) may be between sockets 146 andthe particular group of holder portions 20 which are to be actuated indischarge station 74, and serves to guide workpieces 144 released fromholders 20 into the pockets of sockets 146. Chute assembly 158 includesrigid backing plate 160 extending across the width of and above chamber136 to which rear guide 162 is secured by suitable means such as screws164. Rear guide 162 has extensions 166 in line behind the pockets formedby sockets 146 with lower end portions 163 (FIG. 3) being adjustabletoward and away from such sockets via studs 168 threaded in backingplate 160. Adjacent fingers 170 in front of rear guide 162 secured at172 to backing plate 160 form guide walls on either lateral side of asocket 146, in the form of a vertical portion 174 on one side of asocket and portion 176 on the other side inclined toward the socketaxis, each latter portion 176 also being adjustable crosswise of chamber136 via set screws 178 in elongated slots 180. Front guide plate 182(FIG. 3) of chute assembly 158 extends down in front of the socketsgenerally parallel to rear guide 162 and is pivoted at 184 to stanchion186, the latter in turn being connected via a suitable bracket 193 tobacking plate 160. A plurality of weights 188 bolted at 183 to theunderside of horizontal overhung portion 190 of front guide plate 182(FIG. 5) at intervals across the width thereof urge plate 182 to therear about pivot 184 in the direction of arrow 192 in FIG. 3.

Condition-responsive-means such as microswitch 194 may be adjustablymounted on bracket 193 adjacent the end of overhung portion 190 of plate182, as illustrated in FIG. 3, and includes force-detecting probe 196 innormal contact with the underside of horizontal portion 190. Microswitch194, via suitable conventional electrical wiring is operativelyconnected into the circuits for actuating solenoid valve 130 of triggerassembly 104 and the intermitter for presenting a support assembly 142at discharge station 74.

Collection means including chute 198 (FIG. 2) beneath disc 102discharging to a suitable parts-recovery means, not shown, is provideddownstream of discharge station 74 for accepting parts released fromholders 20 as a result of interfering cooperation between the peripheryof disc 102 and the trip mechanisms of the various carrier assemblies.

In operation, according to the illustrated embodiment, a continuingsuccession of elongated, hollow molded workpieces or parts 144 havingenlarged portions 200 adjacent one open end are sequentially loaded inseries, as schematically illustrated in FIG. 2, either manually or bysuitable automatic means, into holders or clips 20 of individual carrierassemblies 10 via funnels 66 from an upstream area such as a molding ortrimming station 72. As shown in FIG. 3, the only portion of part 144 incontact with any of the components of the apparatus of the invention atany time need only be the relatively limited supported area on theunderside of enlargement 200 resting on the upper surface of clip 20.This is especially important when, for various reasons, minimum contactof the part with the handling apparatus is desirable. As stated,assemblies 10 occupy the full length of chains 76 and 78 whichcontinuously move loaded assemblies 10 in sequence from loading station72 along a longitudinal path toward discharge station 74. At preciselytimed periodic intervals established by conventionally synchronizing theactuation of solenoid valve 130 and the previously mentioned intermitterfor moving sockets 146 into station 74, bar 64 is tripped, i.e., movedto the right from its FIG. 3 position, to simultaneously abruptlyrelease the ends 52 of arm portions 39 from engagement with ledge 54 ofeach of those assemblies which happen at that time to be adjacent bar 64and within such longitudinal path, thus pivoting holders 20 under theinfluence of springs 36 downwardly to their release positions. In sodoing, each part 144 is ejected through open side 30 of a U-shapedholder while movement of its carrier assembly continues through station74, whereupon the part then falls under its own weight into the pocketsformed by sockets 146, or like equipment, waiting below. The releaseaction is similar with the embodiment of FIG. 6 in that platform 21 isabruptly pivoted down from beneath the lower end of a part 144 onactuation of the trigger assembly. The continuously moving unloadedcarrier assemblies are thereupon conveyed back toward loading station 74to pick up additional workpieces. Along the way, follower 24 of eachassembly rides upwardly along edge 134 of cam 132 so as to raise orreset each holder 20 before arriving back at loading station 72.

As can be appreciated, the discharged parts 144 between the holders andsockets will follow a parabolic trajectory as a result of the continuingmovement of the carrier assemblies during discharge. This trajectorywill vary depending (a) on the velocity of chains 76, 78, which can, forexample, reach 75 feet per minute or more, and (b) the weight of theparts 144 which may vary in size and shape. The released parts followingsuch a variable trajectory can be guided into the pockets of thetemporarily restrained sockets by suitably adjusting the variousportions of chute assembly 158 when the latter is used.

After a support assembly 142 (FIG. 5) has been partially or completelyloaded with a plurality of workpieces 144 via engagement of enlargements200 with a step 145 in the base of each socket as generally indicated inFIG. 3, it is released from the station 74 so as to advance throughchamber 136 via engagement with suitable driven chains, not shown, butmore particularly described and illustrated in the previously mentionedcopending application.

In the event a part 144 does not truly seat in the pocket of a socketassembly 146 but rather instead becomes wedged or trapped, for examplebetween adjacent finger guides 170, such malfunction will be sensed whensupport assembly 142 advances away from station 74 in that front guideplate 182 will pivot forwardly under the influence of the wedged part inopposition to the rearward bias generated by weights 188. When thisoccurs, probe 196 of switch 194 breaks contact with plate portion 190and creates an electrical signal rendering solenoid 130 inoperative andtemporarily deenergizing the intermitter supplying support assemblies142 to station 74. Under such condition, successive carrier assemblies10, which continue to move with chains 76 and 78 around the closed path,approach disc 102 in loaded condition which, as previously described,causes release of consecutive parts 144 to chute 198 as a result ofinterfering contact between the periphery of disc 102 and latch 44. Thiscontinues until the temporary system blockage is corrected by removingthe wedged part, which automatically brings weighted plate portion 190back into contact with probe 196, which condition removes the overridingelectrical signal(s) rendering solenoid 130 and the intermitterinoperative, whereupon these latter members again commence to functionin normal manner.

Various modifications and alterations of the invention will be readilysuggested to persons skilled in the art. It is intended therefore, thatthe foregoing be considered as exemplary only and that the scope of theinvention be ascertained from the following claims.

What is claimed is:
 1. Workpiece handling apparatus comprising:A. aplurality of carrier assemblies, each including:a. a holder forsupporting a workpiece; and b. a trip mechanism for abruptly shiftingsaid holder to a workpiece-release position; B. means supporting saidcarrier assemblies for sequential movement along a longitudinal paththrough loading and discharge stations; C. an actuating assembly forsimultaneously triggering the trip mechanisms of a group of saidplurality of carrier assemblies at the discharge station while in saidlongitudinal path; and D. trip mechanism reset means between thedischarge and loading stations for returning the trip mechanisms toworkpiece-engaging positions.
 2. The apparatus of claim 1 wherein eachcarrier assembly further includes upright post means pivotallysupporting said holder, and said trip mechanism includes:i. torsionsprings mounted with the holder and post means biasing the holder towardsaid workpiece-release position; and ii. latch means associated with theholder and post means for securing said holder in its workpiece-engagingposition.
 3. The apparatus of claim 1 including a funnel member abovethe holder.
 4. The apparatus of claim 1 wherein said reset meansincludes a follower projecting from the holder and a cam for coactingwith the follower.
 5. The apparatus of claim 1 wherein said holdercomprises a clip member having a cutout portion open on one side.
 6. Theapparatus of claim 1 wherein said holder comprises a platform forsupporting the lower end of the workpiece.
 7. The apparatus of claim 2wherein said latch means comprises:i. a latch member having arm portionsat one end pivoted to the post means above the holder, said latch memberhaving a cutout portion for securing end portions of the holder thereinagainst bias of the torsion springs to fix the holder in a horizontalposition; and ii. a compression spring beneath the pivot connection ofthe arm portions and post means urging the latch member outwardly awayfrom the post means.
 8. The apparatus of claim 7 wherein said latchmeans further includes a screw adjustably secured in and projecting fromthe latch member toward the post means above the pivoted attachment ofthe arm portions to limit the extent of outward bias of the latch memberby the compression spring.
 9. Workpiece handling apparatus comprising:A.a plurality of upright carrier assemblies, each including a holderportion secured to post means for supporting a workpiece; B. means forabruptly shifting each holder portion with respect to the post means toa workpiece-release position and for returning each holder portion to aworkpiece-engaging position; C. means supporting said carrier assembliesfor sequential movement along a longitudinal path through a loading andsaid discharge stations comprising:a. vertically spaced chains mountedfor continuous movement through an endless path; b. guide bars adjacenteach chain; and c. clips for each carrier assembly slidably stradling aguide bar and secured to the post means and chains at spaced intervalsthereon for stabilizing each carrier assembly during movement with suchchains; and D. a trigger assembly for simultaneously actuating the meansfor abruptly shifting a group of said holder portions of the pluralityof carrier assemblies to said workpiece-release positions while in saidlongitudinal path at a discharge station.
 10. The apparatus of claim 9including coaxial sprockets for said chains on a rotatably mounted shaftdownstream of said discharge station.
 11. The apparatus of claim 10wherein said means for abruptly shifting and returning each holderportion comprises a trip mechanism portion of each carrier assembly. 12.The apparatus of claim 11 including a disc on said shaft between saidsprockets adapted to trigger said trip mechanism portion when a holderis in a workpiece-engaging position as it passes said disc. 13.Workpiece handling apparatus comprising:A. a plurality of uprightcarrier assemblies, each including post means and a holder portion forsupporting a workpiece; B. means for shifting each holder portion to aworkpiece-release position and for returning each holder portion to aworkpiece-engaging position; C. means supporting said carrier assembliesfor sequential movement along a longitudinal path through loading anddischarge stations; D. a trigger assembly at the discharge station forsimultaneously coacting with the holder portions of a series of adjacentcarrier assemblies while in said longitudinal path comprising:a. a barin a substantially horizontal position having a length at least equal tothe portion of the path occupied by the holder portions of said seriesof adjacent assemblies; and b. means for cyclically moving said bar toactuate the means for shifting the holder portions of said series ofadjacent assemblies to workpiece-release positions.
 14. The apparatus ofclaim 13 wherein said means for cyclically pivoting includes:a. linkmembers pivoted to said bar and a rigid support; b. a solenoid valveoperatively secured to said bar and a link member for moving said bar ina first direction; and c. a tension spring operatively associated withthe bar and rigid support urging said bar in a direction opposite tosaid first direction.